Radio antenna



July 7,1936. Q BANKS 2,047,092

RADIO ANTENNA Filed Sept. 5, 1933 V I 35 46 G g 54 5 PAM/o; Renew/1? awe/WWO jra OBzmk Patented July 7, 1936 UNITED; STATES PATENT OFFICE f nAmo ANT NNA" I I v Ira 0. Banks, Higginsville, Mo. Application September 5, 1933,,Serial No. 688,224

" IICIaim. (erase-33 The invention relates to radio antenna and it is. an object. of the invention to providea device for controllingthe effective tone .and volumeof a radio receiver. and .to enable the operator to switch from an outsideantenna to an inside antenna as desired. x I i Another object is toprovide a device of novel construction and arrangement of parts, which may be easily connected to a radio receiver for efiecting such switching operations, all. of which will be hereinafter more fully described and claimed. f

1 The .present invention is an improvement over mypatents for Radio'antenna whichissued .June 13, 1933, as Patents No. 1,914,233,: and No;-

1,914,234, whereby. some of the features of the two disclosures are incorporated with additional features as will be described hereinafter and having greater flexibility and other advantages.

Referring to the accompanying drawing which is made a part hereof and on which similar reference characters indicate similar parts,

Figure 1 is a diagrammatic view of the device connected to a radio receiver.

Figure 2 is a plan view of the top with the operating knob shown in dotted lines, and

Figure 3 is an underside view of the device, showing the details of the resistor.

In the drawing niuneral I indicates a casing provided with a flat plate resistor II mounted therein and having terminals I2 and I3 fixed to the ends thereof. A terminal I4 is provided intermediate the terminals I2 and I3 and is connected to a central shaft I5 having a moving contact I6 fixed thereto adapted to engage the plate resistor II. The resistor is secured to the underside of the top of the housing I8 with the shaft I5 projecting therethrough. The shaft is provided with an operating knob II shown in dotted lines on Figure 2. A switch arm I9 is mounted on the shaft I5 beneath the knob I I and is held in place by a nut turned on the shaft.

The end 2| of the switch arm I9 extends outwardly from the knob and serves as an operating end and the other end 22 is adapted to engage contacts 23 and 24 positioned on the top of the casing and connected to the ends of the resistor plate II. The movement of the arm is limited by the stops 25 and 26 fixed to contacts 23 and 24 respectively.

The terminals I2 and I3 are connected by wires 21 and 28 to the binding posts 29 and 39, respectively. The terminal I4 is connected by a wire 3I to the binding post 32.

Numeral 33 indicates a radio receiver provided with power input leads and 35 connected thereto and antenna post 36 and ground post 31.

'An'outside antenna 38 isconnected to post 36 and to post of the. devicelby means of the wire 39. -Post. 32 is connected to ground wire 46 and post 29 is connected to ground post 31 of the radio receiver by wire 4|; As shown an aux iliary lead 42 from outsideantenna to one of the power input leads 34 is provided. A switch 43 and a condenser 44 are provided in the line 42, the purpose of thisauxiliary lead 42 will be later described. a The radio receiver 33 is also provided with blocking condensers 45 connected between the leads: 34 and 35. A switch 46 is connected in the outside antenna circuit 38.

The operation of the device is as follows:

Considering the device connected as shown in Figure 1 where the radio receiver is grounded at the power input side to the chassis or frame by using blocking condensers or where the electric house circuit is grounded it is advisable to use an auxiliary lead 42 to provide a power lead antenna circuit in any suitable manner; such a circuit is diagrammatically indicated. The other end of the lead 42 is connected to the antenna post of the radio receiver.

By moving the switch arm I9 to contact the terminal 24, signals are received both on the outside antenna and the auxiliary line, the electric house circuit and the device which serves as an indoor antenna and controlled by the device. By moving the arm I6 along the resistor II the volume may be increased or decreased as desired. Should the signals to the radio receiver become noisy due to various disturbances transmitted by the outside or inside antenna this may be reduced by opening either the switch 43 in the auxiliary line or the switch 46 in the antenna 38. It is therefore possible to choose the antenna which will give the best signals. In either case the arm I6 may serve as a vernier when rotated on the resistor.

When the switch arm I9 is positioned between the terminals I2 and I3, it would be necessary in order to obtain similar results to move the arm I6 to contact terminal I2, but the vernier effect of the arm I6 would be lost.

When the switch I9 is placed on contact 23, and switches 46 and 43 closed, the antenna and the receiver are grounded and the apparatus is protected against static or lightning discharges. By opening switch 46, the radio receiver receives signal energy from the power line through condenser N. The volume is regulated by moving contact arm IS on resistor II which is in series with the ground and the input circuit. With the switch l9 between contacts 23 and 24 and the switches 43 and 46 closed, the volume of the signals collected from the antenna 38 and the power line is varied by moving arm [6 over the resistor II which is now connected in shunt to the input circuit. By placing the arm IS on contact 24, all of the resistance between contact l2 and the arm I6 is shorted, giving a diiferent range of control.

The switch arm l9 when positioned intermediate the terminals I2 and i3 is non-effective. The

arm I6 may be rotated to vary the potential drop between the antenna post and ground post of the radio receiver to effect the volume of the signals to the radio receiver.

When it is desired to obtain signals by use of the outside antenna 38, the switch arm I 9 is moved to contact the terminal [2, this makes a direct ground from the ground post of the radio receiver to the outside ground and. the signals are then controlled by movement of the arm l6 and the part of the resistance between the arm I6 and the terminal I2 is non-effective, it being short circuited, the part adjacent the terminal I3 is effective to vary the signals to the radio receiver.

It may be seen that by using a device of the character above described, it is possible to vary the volume of the signal by varying the potential 'drop across the antenna and ground post of the radio receiver and when desirable either the outside antenna or the indoor antenna may be used. The device permits switching from one to the other in order to reduce static and other inter ferences which might be present or transmitted to the radio receiver on one or the other of the antennae, in other words, the novel arrangement of parts and hook-up enables the operator to choose the circuit or antenna most desired for better reception and control of volume of signals 5 received; to eliminate a part of the interference due to atmospheric conditions and to obtain results which might not otherwise be obained unless the device is employed.

It will be obvious to those skilled in the art 1 that various changes may be made in my device without departing from the spirit of the invention and therefore I do not limit myself to what is shown in the drawing and described in the specification, but only as indicated by the appended 15 claim.

Having thus fully described my said invention, what I claim as new and desire to secure by Letters Patent, is:

A variable antenna control for the receiving 20 input circuit of a radio receiver having antenna and ground connecting means and an antenna connected to said antenna connecting means, said control comprising a resistance connected across said connecting means and having a grounded 25 contact engaging said resistance movable to vary the position of contact therewith, and a second movable grounded contact to be selectively connected with either end' of said resistance or disconnected therefrom, whereby the first contact 30 may selectively vary the signal strength and whereby the operation of the second contact may selectively connect the antenna connecting means to ground, the ground connecting means to ground or leave both ungrounded thereby. 35

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